Safari 4 has incorporated CoverFlow into the Bookmarks view. If you find that this is a bit much for you, you can remove CoverFlow so that your bookmarks are simply listed like they used to be.
1. Open Terminal.
2. Execute the following command:
defaults write com.apple.Safari DebugSafari4IncludeFlowViewInBookmarksView -bool NO
Restart Safari. Your bookmarks will no longer be displayed in CoverFlow.
Your Bookmarks view will go from this:
to this:
To return to the CoverFlow display, execute the following command:
defaults write com.apple.Safari DebugSafari4IncludeFlowViewInBookmarksView -bool YES